<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>时间问候</title>
</head>
<style>
    img {
        width: 300px;
    }
</style>

<body>
    <img src="img/zsh.jpg" alt="">
    <div>早上好</div>

    <script>
        var img = document.querySelector('img');
        var div = document.querySelector('div');

        var date = new Date();
        var h = date.getHours;
        if (h < 12) {
            img.src = 'img/zsh.jpg';
            div.innerHTML = '亲，上午好，好好写代码';
        } else if (h < 18) {
            img.src = 'img/xwh.jpg';
            div.innerHTML = '亲, 下午好，好好写代码';
        } else {
            img.src = 'img/wsh.jpg';
            div.innerHTML = '亲，晚上好，好好写代码';
        }
    </script>
</body>

</html>